Cosmetic compositions containing an organic extract of chick peas and methods of conditioning skin by applying such compositions to the skin.
The human skin consists of two major layers, the bottom thicker layer dermis, and the top thinner layerxe2x80x94the epidermis. Dermis is the layer which provides the strength, elasticity and the thickness to the skin.
The main cell type of the dermis is fibroblasts, which is responsible for synthesis and secretion of all the dermal matrix components such as collagen, elastin and glycosaminoglycans. Collagen provides the strength, elastin the elasticity and glycosaminoglycans the moistness and plumpness of the skin. With aging, the thickness of the dermal layer is reduced and this is believed to be partially responsible for the formation of wrinkles in aging skin. The top layer of human skin or the epidermis which provides the resilience and the barrier properties of the skin, is composed of many different cell types including keratinocytes, melanocytes and langerhans cells. Keratinocytes are the major cell type of the epidermis (75-80% of the total number of cells in the human epidermis). Richards et al. reported that estrogen stimulates secretion of a protein, prolactin, by human dermal fibroblast cells and that prolactin then stimulates proliferation of keratinocytes. Richards et al., Human Dermal Fibroblasts Express Prolactin In Vitro., J. Invest. Dermatol., 106: 1250, 1996.
Estrogens and synthetic compounds which act like estrogens are known to increase the thickness of the dermal layer and reduce wrinkle formation in the aging skin. The changes in the skin such as skin dryness, loss of skin elasticity and plumpness occurring after menopause is attributed to the lack of estrogen production. Estrogen therapy prevents or slows down many of these changes associated with aging skin (Creidi et al., Effect of a conjugated estrogen cream on aging facial skin, Maturitas, 19, p. 211, 1994). Some of the effects of estrogen on skin include: increase in skin thickness and disappearance of fine wrinkles, increase of the mitotic rate of the epidermis, reduction in the size and activity of the sebaceous gland, slow down of the rate of hair growth, stimulation of collagen turnover and increase in the production of hyaluronic acid and glycosaminoglycan synthesis of the fibroblasts (Pugliese, Menopausal skin, Skin Inc., March/April 1994: p 69-77).
In recent years, phytoestrogens (i.e., natural compounds which have estrogen-like activity and which are found in plants) have been increasingly used for therapeutic purposes. Some of the uses described are as hypocholesterolemic and antiatherogenic agents, treatment of cardiovascular diseases especially in postmenopausal women, treatment for osteoporosis in the elderly and as an anticancer agent especially against breast cancer, endometrial and cervical cancer in women (Knight et al., Phytoestrogensxe2x80x94a short review, Maturitas, 22: 167-75, 1995).
The consumer demand for xe2x80x9cnaturalxe2x80x9d based products has been growing in recent years. The consumers perceive chemical synthesis as environmentally unsafe. A chemically synthesized ingredient may contain harsh chemicals. Natural products are perceived as pure and mild and superior to chemically synthesized products. However, delivering a cosmetic benefit from plant sources is not trivial. In order to derive a real benefit from a xe2x80x9cnaturalxe2x80x9d source not only a plant or a part of the plant containing a specific active has to be identified, but a minimum concentration and/or a specific extract of that plant has to be identified which truly delivers a cosmetic benefit.
Over 500 compounds present in plants have been described to have estrogenic activity. These compounds, collectively called phytoestrogens, are found in a diverse number of plants including cereals, legumes (including chick peas) and grasses (Price et al., Naturally occurring estrogens in foods- a review., Food additives and contaminants., 2, p. 73-106, 1985). Their concentrations vary in the different parts of the plants, geographical locations, year of growth etc. Two major classes of plant compounds which possess phytoestrogenic activity are flavonoids and coumestans. Some of the commonly described phytoestrogenic compounds are genistein, biochanin A, formononetin, daidzein and their glycoside derivatives (Knight et al., Phytoestrogens-a short review. Maturitas, J. Climactreic and post-menopause, 22, p.167-75, 1995).
Chick pea or Spanish pea (Cicer arietinum), a common dietary lentil, contains flavonoids including daidzein, formononetin, biochanin A, pratensein, homoferreirin, medicarpin, maackiain, methyl coumestrol, medicagol, formononetin glucoside and biochanin A glucoside (Ingham et al., In: Progress in the chemistry of Organic natural products, vol 43: Ed-W. Herz et al., Springer-Verlag, Wien, N.Y., 1983). The flavonoids from chick pea have been reported to have lipid lowering effects in the blood and liver of rats. Several nutritional studies report on the protein from chick pea for use as nutritional supplements and ways to improve the protein quality of chick pea. Vasiliou, U.S. Pat. No. 4,761,285 discloses the use of chick peas as a dietary supplement or for internal or topical treatment of hemorrhoids. In India, a cosmetic mask or skin treatment made from chick pea powder mixed with water is a common beauty treatment.
The art discussed above does not describe organic chick pea extracts for skin care or cosmetic use. The art does not teach topical application of organic chick pea extracts, as a phytoestrogen, and with a specified estrogenic activity.
The present invention includes a skin care composition comprising:
(i) an organic extract of chick peas in an amount such as to provide an estrogenic activity equivalent to at least 1 nM of estradiol, the estrogenic activity being determined by the test described herein;
(ii) a cosmetically acceptable vehicle.
The present invention also includes a method of improving or preventing the condition of wrinkled, lined, dry, flaky, aged or photodamaged skin and improving skin thickness, elasticity, flexibility and plumpness, which method includes applying to the skin the inventive composition. Compositions of the invention are intended for topical application to mammalian skin which is already dry, flaky, lined, wrinkled, aged, photodamaged, or the inventive compositions may be applied prophylactically to normal healthy skin to prevent or reduce the deteriorative changes.
The present invention also includes a cosmetic method of increasing fibroblast and epidermal skin cell proliferation in human skin by applying to the skin the inventive composition.
Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word xe2x80x9cabout.xe2x80x9d All amounts are by weight of the composition, unless otherwise specified.
Chick Peas
Chick peas are suitable for use in the inventive compositions in the form of an organic extract. The chick pea extract is prepared for use in the present invention from dried chick peas. Dried chick peas may be obtained from Arrowhead Mills, from health food stores or supermarkets.
The organic chick pea extracts are prepared by extracting the. dried chick peas with a solvent by stirring 1 part of dried chick peas with 2 to 5 parts of the solvent for from 4 to 24 hours at room temperature. Suitable solvents are described hereinbelow. The extracts are clarified by filtration and/or centrifugation, then dried by evaporation (optionally, under vacuum) to obtain the organic chick pea extract.
Solvents suitable for: the preparation of chick pea extract for use herein include, but are not limited to: ethanol, methanol, hexane, chloroform, dichloromethane and ethyl acetate. The preferred solvents are dichloromethane, methanol, or ethanol in order to optimize activity. The extract may be further concentrated, fractioned, re-extracted or purified, e.g. by organic solvent extraction or by chromatography.
It has been found, as part of the present invention, that the organic chick pea extract has to be employed in a specific minimum amount to deliver an estrogenic activity.
Chick pea extract or powder is employed in an amount of from 0.0001 to 50%, as long as it delivers the estrogenic activity equivalent to at least 1 nM, generally in the range of from 1 nM to 100 nM, of estradiol. Estrogenic activity of the chick pea extract is determined by comparison to the activity of 1 nM estradiol using ZR-75 cells in a side by side experiment, as described in Example 1 below. Preferably, the chick pea extract is employed in an amount such as to deliver the estrogenic activity equivalent to at least 2 nM of estradiol.
Cosmetically Acceptable Vehicle
The composition according to the invention also comprises a cosmetically acceptable vehicle to act as a diluant, dispersant or carrier for the chick pea extract in the composition, so as to facilitate its distribution when the composition is applied to the skin.
Vehicles other than or in addition to water can include liquid or solid emollients, solvents, humectants, thickeners and powders. An especially preferred nonaqueous carrier is a polydimethyl siloxane and/or a polydimethyl phenyl siloxane. Silicones of this invention may be those with viscosities ranging anywhere from about 10 to 10,000,000 mm2/s(centistokes) at 250xc2x0 C. Especially desirable are mixtures of low and high viscosity silicones. These silicones are available from the General Electric Company under trademarks Vicasil, SE and SF and from the Dow Corning Company under the 200 and 550 Series. Amounts of silicone which can be utilized in the compositions of this invention range anywhere from 5% to 95%, preferably from 25% to 90% by weight of the composition.
The cosmetically acceptable vehicle will usually form from 5% to 99.9%, preferably from 25% to 80% by weight of the composition, and can, in the absence of other cosmetic adjuncts, form the balance of the composition. Preferably, the vehicle is at least 80 wt. % water, by weight of the vehicle. Preferably, water comprises at least 50 wt. % of the inventive composition, most preferably from 60 to 80 wt. %, by weight of the composition.
Optional Skin Benefit Materials and Cosmetic Adjuncts
An oil or oily material may be present, together with an emulsifier to provide either a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average hydrophilic-lipophilic balance (HLB) of the emulsifier employed.
The inventive compositions preferably include sunscreens. Sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone are commercially available under the trademarks, Parsol MCX and Benzophenone-3, respectively. The exact amount of sunscreen employed in the emulsions can vary depending upon the degree of protection desired from the sun""s UV radiation.
Emollients are often incorporated into cosmetic compositions of the present invention. Levels of such emollients may range from 0.5% to 50%, preferably between 5% and 30% by weight of the total composition. Emollients may be classified under such general chemical categories as esters, fatty acids and alcohols, polyols and hydrocarbons.
Esters may be mono- or di-esters. Acceptable examples of fatty di-esters include dibutyl adipate, diethyl sebacate, diisopropyl dimerate, and dioctyl succinate. Acceptable branched chain fatty esters include 2-ethyl-hexyl myristate, isopropyl stearate and isostearyl palmitate. Acceptable tribasic acid. esters include triisopropyl trilinoleate and trilauryl citrate. Acceptable straight chain fatty esters include lauryl palmitate, myristyl lactate, and stearyl oleate. Preferred esters include coco-caprylate/caprate (a blend of coco-caprylate and coco-caprate), propylene glycol myristyl ether acetate, diisopropyl adipate and cetyl octanoate.
Suitable fatty alcohols and acids include those compounds having from 10 to 20 carbon atoms. Especially preferred are such compounds such as cetyl, myristyl, palmitic and stearyl alcohols and acids.
Among the polyols which may serve as emollients are linear and branched chain alkyl polyhydroxyl compounds. For example, propylene glycol, sorbitol and glycerin are preferred. Also useful may be polymeric polyols such as poly-propylene glycol and polyethylene glycol. Butylene and propylene glycol are also especially preferred as penetration enhancers.
Exemplary hydrocarbons which may serve as emollients are those having hydrocarbon chains anywhere from 12 to 30 carbon atoms. Specific examples include mineral oil, petroleum jelly, squalene and isoparaffins.
Another category of functional ingredients within the cosmetic compositions of the present invention are thickeners. A thickener will usually be present in amounts anywhere from 0.1 to 20% by weight, preferably from about 0.5% to 10% by weight of the composition. Exemplary thickeners are cross-linked polyacrylate materials available under the trademark Carbopol from the B.F. Goodrich Company. Gums may be employed such as xanthan, carrageenan, gelatin, karaya, pectin and locust beans gum. Under certain circumstances the thickening function may be accomplished by a material also serving as a silicone or emollient. For instance, silicone gums in excess of 10 centistokes and esters such as glycerol stearate have dual functionality.
Powders may be incorporated into the cosmetic composition of the invention. These powders include chalk, talc, kaolin, starch, smectite clays, chemically modified magnesium aluminum silicate, organically modified montmorillonite clay, hydrated aluminum silicate, fumed silica, aluminum starch octenyl succinate and mixtures thereof.
Other adjunct minor components may also be incorporated into the cosmetic compositions. These ingredients may include coloring agents, opacifiers and perfumes. Amounts of these other adjunct minor components may range anywhere from 0.001% up to 20% by weight of the composition.
Use of the Composition
The composition according to the invention is intended primarily as a product for topical application to human skin, especially as an agent for conditioning, moisturizing and smoothening the skin, increasing its thickness, flexibility and elasticity and preventing or reducing the appearance of wrinkled, lined or aged skin.
In use, a small quantity of the composition, for example from 1 to 100 ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then. spread over and/or rubbed into the skin using the hand or fingers or a suitable device.
Product Form and Packagina
The topical skin care composition of the invention can be formulated as a lotion, a cream or a gel. The composition can be packaged in a suitable container to suit its viscosity and intended use by the consumer. For example, a lotion or a cream can be packaged in a bottle or a roll-ball applicator, or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar. The composition may also be included in capsules such as those described in U.S. Pat. No. 5,063,507, incorporated by reference herein. The invention accordingly also provides a closed container containing a cosmetically acceptable composition as herein defined.